mm: use helper for calling f_op->mmap()

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
diff --git a/mm/nommu.c b/mm/nommu.c
index 24f9f5f..e366354 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1084,7 +1084,7 @@ static int do_mmap_shared_file(struct vm_area_struct *vma)
 {
 	int ret;
 
-	ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
+	ret = call_mmap(vma->vm_file, vma);
 	if (ret == 0) {
 		vma->vm_region->vm_top = vma->vm_region->vm_end;
 		return 0;
@@ -1115,7 +1115,7 @@ static int do_mmap_private(struct vm_area_struct *vma,
 	 * - VM_MAYSHARE will be set if it may attempt to share
 	 */
 	if (capabilities & NOMMU_MAP_DIRECT) {
-		ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
+		ret = call_mmap(vma->vm_file, vma);
 		if (ret == 0) {
 			/* shouldn't return success if we're not sharing */
 			BUG_ON(!(vma->vm_flags & VM_MAYSHARE));